A properly organized opt-in mailing list can be a very powerful tool when marketing your crafts. Remember, that whether you create an online mailing or a real-world physical mailing you must create your list from people who have actually agreed to accept the mailing. If you simply add people to your list without permission you will not only be wasting your time, but you may actually be breaking the law as well! Once created, use your list to let your customers know about events you will be attending in their area, new products and any special sales you will be having.